In the Authorized Toyota Dealer and Service, I checked Toyota Sienna 2015 which was serviced only there for the passed 3 years. It has 106,000 km on it now. The yellow engine warning sign was on and warning white writing was blinking Require Engine Check. I asked to print all the services being provided and the oil 0W20 Toyota brand was changed at 30k km, 60k km, 90k km. It is one of those expended life oils for 20k miles. The warning signs starts blinking each time after driving for 15k km after oil changed, but it is ignored. The service people say that everything is fine with the car. I can buy it and start changing the oil every 15k km, but I wonder could the damage be done, but it doesn't just show it yet. What should I look for during the computer hook up inspection to spot the potential damage?
30,000kms pms interval is a looooong time. Have it checked with your trusted mechanic. Those service lights turns on typically when it's programmed that you had run the required KMs for you to have it serviced. But I think it's best to see if there are any trouble codes, check the engine's life too. 30,000kms can cause sludge to build up.
And you can change the oil much frequently, to keep the engine healthy. Say 7,500kms or so.
What's really involved is both a visual inspection and scan data: Long term and short term fuel trim, operating temperature of the engine, among other things, would show up on scan data. Visual inspection (small scope) would reveal how carboned up valves might be, and how worn (grit will wear down cylinders and pistons). To determin if your vehicle is burning oil, swipe the end of the tailpipe with your fingers. If it's black, this Sienna is burning oil.
All Toyotas burn some oil. And your oil change interval should be even less, every 9-10K.
Don't take it from me. Take it from a Toyota Master Diagnostician, AMD: The best discussion of oil consumption issues of Toyotas (and what you can do about it). This is must viewing for you.
https://www.youtube.com/watch?v=v4JS7PybV2k
Could the engine be damged during that time? What should I do to make sure it is all good from now on?
Recently Toyota changed oil change interval form 8000km to 16000km. Especially they use 0w20 oil. Double check if your car can stand that long. Typically oil life won’t be longer than 16000km.
As Scotty says, oil is cheap and engines are expensive. I change mine every 3 to 5k miles with Castrol GTX full syn(full syn is pretty much necessary) in my Scion iM and works fantastic. 48k miles so far.
